The term ‘lateral thinking’ was coined by Edward de Bono to denote a problem-solving style that involves looking at the given situation from unexpected angles. Sometimes a problem seems difficult or insoluble because our assumptions about it are wrong.
A classic example: A father and his son are involved in a car accident, as a result of which the son is rushed to hospital for emergency surgery. The surgeon looks at him and says “I can’t operate on him, he’s my son”. Explain.
A variant of this involves a father and son travelling on a scheduled flight; the father asks the flight attendant if his son may visit the cockpit and she takes him there. When he’s gone the pilot explains to the co-pilot “That was my son”. For a few people there’s no ‘puzzle’ here, but most of us are so used to seeing only male surgeons and pilots that we too easily overlook the obvious explanation: the pilot or surgeon is the boy’s mother.
To solve these puzzles you’ll need to check your assumptions, especially about who, what, when, where, why?. Some won’t yield to that approach, and demand a flash of inspiration, such as:
A landlord is threatening to evict a father and his beautiful young daughter, unless she agrees to marry him. In a false gesture of sincerity, he offers her an opportunity for her and her father to remain in the house, without marrying him. He has a silk bag in which he says he has placed a white and a black stone from the footpath on which they’re standing. If she picks the white stone from the bag, without looking, she wins; if she picks the black, she loses. However, the young girl saw him place two black stones in the bag. She can’t expose him in front of the witnesses without angering him and making things worse. How does the clever girl win? Answer
In this puzzle, there are no tricks – everything is pretty much as it seems. It calls for a novel solution. Well, perhaps it could be argued that the assumption that needs checking is the one about how the drawn stone is known…
So, be prepared to think outside the box for these classic lateral thinking puzzles. Enjoy!
Three Switches and Three Bulbs
Three switches outside a windowless room are connected to three light bulbs inside the room. How can you determine which switch is connected to which bulb if you may enter the room only once? Answer
A man is replacing a wheel on his car, when he accidentally drops the four nuts used to hold the wheel on the car, and they fall into a deep drain, irretrievably lost. A passing girl offers him a solution which enables him to drive home. What is it? Answer
You are on an island (in the center) that is one mile long and 100 yards wide. The vegetation is very dry from a long drought. Suddenly it catches fire at one end of the island, and a strong wind is blowing it towards you, burning the whole width of the island. There’s no beach, only sheer cliffs, and the sea is infested with sharks. What can you do? Answer
How to Age Quickly?
The day before yesterday, Jenny was 17 years old. Next year, she’ll be 20 years old. How is this possible? Answer
Gunshot in the Bar
A man enters a bar and asks for a glass of water. The bartender draws a gun and shoots into the ceiling. The man thanks him and walks out. Why?Answer
Lift the Bridge?
A truck is stuck at a road under a bridge. It’s just a couple of inches too high to pass under. Any other route, avoiding the bridge would add a couple of hours to the journey. A young boy comes along and again saves the day. How? Answer
The Man in the Elevator
A man lives on the tenth floor of a building. Every day he takes the elevator to go down to the ground floor to go to work. When he returns he takes the elevator to the 7th floor and walks up the stairs to reach his apartment on the 10th floor. He hates walking so why does he do it? Clue: on rainy days he goes up in the elevator to the tenth floor. Answer
The Man who Hanged Himself
A large wooden barn is completely empty except for a dead man hanging from the middle of the central rafter. The rope around his neck is ten feet long and his feet are three feet off the ground. The nearest wall is 20 feet away from the man. It is not possible to climb up the walls or along the rafters. The man hanged himself. How did he do it? Answer
Death in a Field
A man is lying dead in a field. Next to him there is an unopened package. There is no other creature in the field. How did he die? Answer
Anthony and Cleopatra are lying dead on the floor of a room. Nearby is a broken bowl. There is no mark on either of their bodies and they were not poisoned. How did they die? Answer
The Coal, Carrot and Scarf
Five pieces of coal, a carrot and a scarf are lying on the lawn. Nobody put them on the lawn but there is a perfectly logical reason why they should be there. What is it? Answer
Trouble with Sons
A woman had two sons who were born on the same hour of the same day of the same year. But they were not twins. How could this be so? Answer
Push that Car
A man pushed his car. He stopped when he reached a hotel at which point he knew he was bankrupt. Why? Answer
A man rode into town on Friday. He stayed for three nights and then left on Friday. How come? Answer
A blind beggar had a brother who died. What relation was the blind beggar to the brother who died? (Brother is not the answer). Answer
Swimmer in the Forest
Deep in the forest was found the body of a man who was wearing only swimming trunks, snorkel and facemask. The nearest lake was 8 miles away and the sea was 100 miles away. How had he died? Answer
The Prisoner and the Police Car
A man has recently escaped from prison and is making his way home on foot. He is walking along a straight rural country lane in bright daylight. He has walked about two miles from the prison, when he sees a police car coming toward him. Despite knowing that all squads would be out looking for him, he ran towards the car for a short while, and only when he was about ten feet away, did he turn and run into the woods to hide. Why did he run towards the police car? Answer
Arthur and The Burglars
Arthur lives with his parents in Chicago. Last week, while his parents were out, Arthur’s next-door neighbor Sophie came round to spend the evening. At one point, she popped out to buy some cigarettes. Just then, two men burst into the apartment and, ignoring Arthur, took the TV set, the stereo and a computer. Arthur had never seen the men before, and they had no legal right to remove the equipment, yet he did nothing to stop them. In fact, he didn’t even act surprised by their behavior. Why not? Answer
During World War II, three Russian V.I.P.’s, Molotov, Vishinsky and Malenkov, were travelling on a train in Russia. Suddenly the train entered a tunnel without the conductor’s turning on the lights. The tunnel was long and sooty. At the moment the train emerged, Stalin wandered into the car and noticed that the men had become spotted with soot.
He said to them: “Before I show you a mirror, I have an idea. Your answers will show me which of you is the quickest thinker.”
The three men immediately sat up and paid strict attention, for each was anxious to show Stalin how smart he was.
“Now,” said Stalin, “each of you gentlemen will please look at the other two, and if you see one whose forehead is smudged with soot, raise your hand.”
All three quickly raised their hands.
Stalin continued, “As soon as any one of you knows with certainty whether he himself has been smudged or not, drop your hand.”
Looking at each other for a few moments, the three men kept their hands raised. Then Malenkov dropped his hand and said, “I know. I am smudged.” Could he really have known? Or was he guessing?
Solved by R.N.Radhakrishnan, Hyderabad, India:
Malenkov knew he was smudged only because the other two did not claim the same!
explanation : if Malenkov is not smudged, then Molotov can see so, and yet he finds Vishinsky with his hand raised. Which tells him (Molotov) that Vishinsky has raised his hand on seeing Molotov’s smudged face, so Molotov should have claimed that he himself was smudged. The fact that he did not so claim, shows that he was confused whose smudged-face was prompting Vishinsky’s raised hand. Hence Malenkov is convinced about his own smudge.
This is correct. At first, the puzzle apears insoluble since the situation is perfectly symmetric, and nobody has access to any information not held by the others. Solving it requires “stepping back” and thinking about what the other Russians could be thinking… In case the answer above isn’t immediately clear, try considering the 2 possibilities where all three have raised their hands:
- Only two people were smudged. Those two would have seen that one person was not smudged, and would have deduced that they themselves must be smudged because the person they see as smudged has their hand up. They would then have lowered their hands.
- All three were smudged. All three could have realised that this was the case, and lowered their hands.
It seems to me that this puzzle hinges on the assumption that these are three intelligent people; case #1 would have been immediately clear to them. The fact that the others didn’t immediately put down their hands was the clue that the situation was perfectly symmetric…
With reference to your Russian tunnel problem I slightly disagree with your answer basically due to the wording of the question. The only way that Malenkov could have known if he was smudged was if one of the other 2 wasn’t smudged. The other smudged face could obviously have also realised this but there is no indication that they would continue to drop their hands once they had realised as Stalin had only asked for someone to drop their hand once they were certain on whether they were smudged or not. This is essentially the same as the original response.
Scenario 2 however, with all 3 smudged, is incorrect as none of them can know for certain whether he is smudged or not. To be absolutely certain would require relying on the intelligence and lateral thinking of the others to make the claim before Malenkov. Otherwise if Vishinsky or Molotov for example weren’t smart enough to claim that they knew they were smudged because Malenkov wasn’t then Malenkov would have to rely on the fact that they were smart enough to work it out. I’m basing this argument on the fact that VIP means Very Important Person which we all know doesn’t equate to Very Intelligent person.
And here’s another twist, from M. Lyons:
I have another solution. It requires deductive thinking on the part of the russian who raised his hand.
He can see both of the other men’s faces, and sees that they are smudged. He can also see their hands, and can see that both other men’s hands are sooty also. He CAN see his own hand, which is sooty. He can therefor conclude, logically that A) We were all in the same car, on the same train, at the same time, going through the same tunnel. Both of the others got soot all over their bodies, including head and hands. B)I did nothing to prevent myself from getttin soot on my face, and C) I can see that my hand is sooty. Therefore, it is logical that I also have soot on my face.
The fact that he is the first one to lower his hand is a testament to his own quick thinking.
Stalin then promoted him to some important position, and he was later executed. The other two men lived long lives of obscurity as factory workers.